Collaborative data sharing via update exchange and provenance

Recent work [Ives et al. 2005] proposed a new class of systems for supporting data sharing among scientific and other collaborations: this new collaborative data sharing system connects heterogeneous logical peers using a network of schema mappings. Each peer has a locally controlled and edited database instance, but wants to incorporate related data from other peers as well. To achieve this, every peer's data and updates propagate along the mappings to the other peers. However, this operation, termed update exchange, is filtered by trust conditions—expressing what data and sources a peer judges to be authoritative—which may cause a peer to reject another's updates. In order to support such filtering, updates carry provenance information. This article develops methods for realizing such systems: we build upon techniques from data integration, data exchange, incremental view maintenance, and view update to propagate updates along mappings, both to derived and optionally to source instances. We incorporate a novel model for tracking data provenance, such that curators may filter updates based on trust conditions over this provenance. We implement our techniques in a layer above an off-the-shelf RDBMS, and we experimentally demonstrate the viability of these techniques in the Orchestra prototype system.